Seattle made the roster move, retroactive to April 22, on Monday before opening a three-game series against Houston. The Mariners recalled right-hander Mayckol Guaipe from Triple-A Tacoma to take Benoit's roster spot.
Benoit has been Seattle's main reliever in the eighth inning this season but was unavailable for a couple of games earlier this month due to the shoulder. Benoit has appeared in five games this season and given up two earned runs in his five innings pitched. Seattle manager Scott Servais said he expects to be without Benoit for two or three weeks.
Guaipe made his major league debut with Seattle last season. He had three saves in six games this season with Tacoma.